Compound for resharpening files.



UNTTE STATES ATENT Fries.

JOHN F. REVALK, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO THE CRESCENTFILE COMPANY, OF CALIFORNIA.

COMPOUND FOR RES HARPENING FILZES.

SPECIFICATION forming part of Letters Patent No; 633,489, datedSeptember 19, 1899.

Application filed March 7, 1899. Serial No. 708,155. (No specimens.)

To (all whom it nuty concern:

Be it known that I, JOHN F. REVALK, a citizen of the United States,residing at San Francisco, in the county of San Francisco and State ofCalifornia, have invented certain new and useful Improvements inCompounds for Resharpening Files, &c., of which the fol lowing is aspecification.

My invention is an improved composition for resharpening files, rasps,and like tools and implements having serrated surfaces.

The object of my invention is to furnish a composition that will acteffectively to sharpen such tools when used with a blast, steam-jet, orother forcing or impelling means. Many attempts have been made toresharpen tools of this character by the use of a sand-blast; but thegritty character of sand, no matter how fine, has made such attempts, sofar as I am aware, unsuccessful, for the reason thatsand destroys theserrated surface bybreaking the teeth instead of sharpening them.

My new composition is composed of elements which when dry constitute anearly impalpable powder without any gritty quality, but which,nevertheless, is exceedingly effective as a resharpening agent.Moreover, the basis or principal ingredient in my compound I utilize aparticular waste product especially adapted to my purpose, and therebymake it of some commercial value. This product is a residuum left afterthe separation of the precious metals from their oresby the wet processof washing and concentration. The ores (quartz or porphyry or acombination of both) are pounded in stamp-mills to a powder, the freegold amalgamated, and the wet pulp fed to concentrator-tables orshaking-belts, where a further concentration takes place. The heavierparticles are retained on the tables orbelts,while the lighter materialis run off either to waste or into settlingtanks. In such tanks afurther separation takes place by gravity, the sand and heavierparticles sinking, while the lighter slimes, as they are termed, remainnearer the top. These concentrator-slimes are composed offinely-connninuted quartz or por phyry and water and are of a smoothgreasy character,'the mineral matter being practically impalpable. Thismineral matter, however, is of the hard abrasive nature suitable for mypurpose, without being gritty, and hence destructive. In one hundred(100) parts of my compound I use about eighty-five (85) parts of thisconcentrator-slime, about five (5) parts of calcium carbonate, aboutfive (5) parts of powdered corundum, and about five (5) parts of causticpotash. These elements, being mixed together, are treated with asufficient quantity of water in a suitable vessel, being washed andstirred therein for a sufficient time, as in lixiviation, and then drawnoff from the upper part of the vessel.

It is not necessary in all cases to use lime in the preparation of thecompound, but as most slimes contain graphite to some extent in suchcases I prefer to use lime to neutral ize its greasy nature.

Powdered corundum is added in a small quantity on account of itsexceptional abrasive quality and caustic potash because of its effect asa cleansing agent when brought in contact with the oil and dirt on thesurfaces of the files to be sharpened.

The compound in use is mixed with water and ejected through a suitablenozzle against the surface of the file, the latter being held at anangle, so that the impact is against the inclined rear surfaces of theteeth. These surfaces are thereby worn down, so that the blunt edges areeffectively restored to their original sharp condition. Any kind of animpelling force may be used; but I prefer a jet of steam, which alsoassists in cleansing the surface of the file.

I do not wish to confiuemyself to the exact proportions stated, as theymay be varied to some extent to conform to the specific nature of theslime which forms the principal ingredient. I have given ingredients andproportions which form a practical and efiective composition for thepurpose and which I have successfully used; but such proportions aresusceptible of reasonable variation,according to the observation andexperience of those skilled in the art.

Having thus described my invention, what I claim as neW and desire tosecure by Letters In testimony whereof I have affixed my sig Patent, isnature, in presence of two witnesses, this A compound for resharpeningfiles and like 20th day of February, 1899. implements composed ofconcentrator-slime, JOHN F. REVALK 5 corundum, calcium carbonate, andcaustic Vitnesses:

potash combined in substantially the propor- L. W'. SEELY,

tions specified. H. J LANG.

